Piston skirt expander



March 25, 1947. M. E. SIPE 2,418,053

' PISTON SKIRT EXPANDER Filgd Jan. 19, 1946 min-1mm I MARTIN E SIP/z INVENTOR- Ftumey v Patented Mar. 25, 1947 UNITED STATES PATENT OFFICE PISTON SKIRT EXPANDER Martin E. Sipe, Denver, Colo.

Application January 19, 1946, Serial No. 642,287

' 2 Claims. 1

This invention relates to improvements in means for expanding slotted skirt pistons.

One of the objects of this invention is to provide an improved expander for maintaining the slotted skirt of a piston of an internal combustion engine and the like in proper engagement with the cylinder wall.

Another object of this invention is to produce an expander of the type indicated which shall be formed from two substantially identical parts that can be constructed by means of a single die.

Another object of the invention is to produce an expander of such construction that before it is put into position in a piston some of the parts thereof are held under stress in a distorted condition by means which can readily be released after the expander has been positioned in the piston, whereby the expander can be readily placed in position and then have the parts released so as to apply to the inner surface of the piston wall, forces sufficiently to accomplish the expansion desired.

Another object of the invention is to produce a two-part expander in which the two parts, when assembled, assume the form of an elongated hexagon and in which the movable portions are situated wholly on the outside of the hexagon.

The above and any other objects that may appear as this description proceeds are attained by means of a construction and an arrangement of parts that will now be described in detail, and for this purpose reference will be had to the accompanying drawing in which the invention has been illustrated in its preferred form, and in which:

Figure l is an end view of a split skirt piston looking in the direction of arrows ll in Figure 2; and shows the expander in position therein;

Figure 2 is a partial section taken on line 2--2, Figure 1;

Figure 3 is an end view of the expander looking in the direction of arrows 33, Figure 2;

Figure 4 is a top plan view of one of the parts of the expander showing certain parts thereof held under strain; and

Figure 5 is a side elevation of the part shown in Figure 4, looking in the direction of arrow 5.

In the drawing reference numeral l designates the skirt of a piston which is slotted as indicated at H, and reference numerals l2 designate the piston pin bosses, while reference numeral I3 designates the piston pin.

The expander consists of two identical parts, each of which has a fiat side It provided with an opening l for the reception of the piston pin.

2 At the ends of the straight portion 14, the material is curved inwardly so as to form inclined sections I6, each of which is provided with an outwardly curved portion I! that terminates in an extension l8. The ends of extensions l8 are provided with spaced slits forming tongues [9' that are bent into a hook-like shape and which serve as anchors for holding the parts I! in contracted condition against heavy strains. The upper edge of each expander element is provided with oppositely extending tongues 20 that are bent inwardly and which are of such length that they overlap when the parts are assembled as shown in Figure 1, tongues 20 may then be secured together by means of spotwelding or other suitable means so as to hold the two parts of the expander in proper assembled position for handling and for positioning in the piston.

When the expander is manufactured and tempered, it has a shape substantially like that shown in Figure 1. The expander parts are then subjected to a bending operation in a suitable machine which curves the parts I'I into a position like that shown in Figure 4, in which tongues [9 project into and through holes 2| in parts l5. Tongues l9 are rearwardly curved before the parts are tempered so that they will function to resist the strains that tend to move parts I! and I8 from the position shown in Figure 4 to that shown in Figure 1.

The two parts having their outwardly curved ends latched in strained position are assembled into the form of an elongated hexagon as shown in Figure 1 and are then attached to each other by spotwelding or some similar means.

The expander is positioned in the cylinder by first removing the wrist pin, then inserting the expander and replacing the wrist pin. After the expander is in position, a screwdriver or other similar tool is introduced into the angle between parts l6 and I8 and the outwardly curved portions released by withdrawing tongues I 9 from holes 2|. As soon as the outwardly curved parts are released, they move into the position shown in Figure 1, whereupon the outer surfaces of the curved portions I! come into contact with the inner surface of the piston skirt and exert forces thereon tending to expand the latter. pander is made from a high grade spring steel and since parts I! have considerable width, they exert a strong expanding force that keeps the piston skirt in properly spaced relation with respect to the inner surface of the piston. The value of the expanding force can be controlled The ex- 3 by a proper selection of the thickness and width of the material employed.

Particular attention is called at this point to the fact that the curved parts I l and I8 lie wholly on the outside of the elongated hexagon and they therefore have plenty of room within which to move so as to exert their maximum expanding pressure.

The positioning of. curved portions l! on the outside of the hexagon instead of on the inside as in some previous devices makes it possible to employ extensions I8 of considerable length that may have tongues l9 formed therein for anchoring purposes. Another advantage due to this construction is that the curved portions H can be more readily put under the desired strains than if the ends were inwardly curved. Tongues 20 serve merely as means for holding the two parts in assembled position and do not function as springs. Tongues 20 are preferably connected by spotwelding, but any other means may be employed. 1

Another feature to which attention is called is that tongues 19 are integral with parts it. In the drawing the tongues have been shown as formed in the ends of parts It? by inwardly ex-' tending slits; of course it is to be understood that this is merely illustrative and that they may be formed in any manner desired. It is, of course, permissible to reverse the arrangement shown having the tongues on part I6 and the holes in the end portions I8.

Instead of using a slotted skirt, as shown in the drawing, the skirt may be made continuous and of somewhat thinner material and the outer surface, instead of being circular, may be somewhat elliptical so as not to contact the inside of the cylinder at the ends of the wrist pins. Pistons of the type referred to as trunk pistons, employ a skirt that is slightly elliptical. Regardwholly on the outside of the hexagon, and readily releasable means comprising an integral tongue on one part for engagement in an opening in the other part for holding the reversely bent ends under strain.

2. A piston skirt expander from leaf spring metal adapted to extend across the skirt of a piston, comprising two identical sections arranged in opposed relation to form a generally approximatel hexagonal elongated structure, the ends of each section being outwardly and rearwardly curved forming an expansive formation lying wholly on the outside of the hexagon, the freeends of the curved portions and the adjacent side of the corresponding section having means for latching the ends in strained position, comprising an integral tongue on one part for operative engagement in a hole in the other part. MARTIN E. SIPE.

REFERENCES CITED The following references are of record in' the file of this patent:

UNITED STATES PATENTS Number Name Date 2,374,463 Sipe Apr. 24, 1945 1,982,706 Teetor Dec. 4, 1934 

